Theory And Experiment Study Of The Single-stage Pulse Tube Refrigeration

Pulse tube cooler is a mini —type refrigeration system without moving parts at low temperature have researched by many countries and has made a great achievement so far. The single-stage pulse tube cooler with a double-inlet has reached the temperature of about 11K with no-load. However, the experimental results reveal that the low temperature is not steady with big load. This paper focus on investigating the temperature-drift phenomenon by numerical simulation and experimental study.1) Numerical simulation of pulse tube coolerComputational Fluid Dynamics (CFD) soft package FLUENT6.1 has been applied for research of the orifice pulse tube cooler system with stainless steel screen as the matrix of the regenerator. Results show that due to occurrence of the vortex induced from the uneven temperature distribution in the cross section area of the heat exchanger, the velocity at the cold end of the pulse tube is disturbed, which makes the temperature fluctuate acutely. The gas temperature near the hot end heat exchanger is a little higher than the ambient temperature. No obvious axial temperature distribution is found.2) Experimental investigation on the pulse tube coolerThe feasibility of the regenerator to controling temperature stability by changing the filling is experimentally and theoretically investigated. Three filling modes which include pure stainless steel screen, l/3Pb+2/3 stainless steel screen, l/3Er3Ni+2/3 stainless steel screen, are used to in the experiment. Results show that complex filling mode increases flow resistance of the regenerator, which helps to stabilize the cooler with high thermal loads for a long time as results of the reduction and stabilization of the disturbing DC-flow, when temperature at cold end is unsteady, the by-pass valve is adjusted so that the gas piston is reset, which makes the temperature stabilize longer. The experimental results provide two ways to restrict cold-end temperature instability at high thermal load for the double-inlet pulse tube refrigeration system.